Breast Cancer Screening in 2025: Mammography, MRI, or More?

Will we still be using mammography for breast cancer screening one fourth of the way through this century? That was the question posed in one session at ECR 2011, and speaker Christine Kuhl said she greatly fears that we actually may.

"Why not use what we already have for screening?" she asked (and not for the last time). "MRI."
People discount MRI because it's expensive, difficult to read, scary for patients, and "drives radiologists crazy," she went on. But it's "a young method, just past its teething troubles." Results from published multicenter trials downplay the use of MRI for breast screening, added Kuhl, but their results are worse than its potential because so many radiologists in those studies didn't know about the latest diagnostic criteria or how to use the magnets adequately.

Kuhl, who is a diagnostic and interventional radiologist at the University of Aachen in Germany, headed the prospective multicenter EVA trial recently published in the Journal of Clinical Oncology, which screened 687 women at high risk of breast cancer, comparing the effectiveness of mammography, ultrasound, MRI, and breast self-examination. MRI was far the most effective, tending to identify cancers at an earlier stage than either mammography or ultrasound.

"Mammography is not the perfect tool as we radiologists would like to see it or as it is portrayed to the public," she said. With its high false-positive rate, its limited sensitivity for invasive breast cancers, and its mere 36 percent sensitivity in women with dense breasts, Kuhl seemed mystified as to why it is still accepted at all. She scoffed at suggestions that adding ultrasound would make it more effective.

"The average exam time would be 21 minutes per woman," she said. At the usual reimbursement rates, she pointed out, "that would have to be considered the most expensive breast cancer screening method."

As to arguments that MRI cannot be recommended for screening without randomized trials, Kuhl countered that the most important evidence is already in after 40 years of mammography: Early detection of breast cancer does lead to better survival.

What we really need for breast cancer screening, said biophysicist Marin Yaffe of Toronto's Sunnybrook Health Sciences Center, is something like they use at the airport: a highly sensitive first-pass scanner, followed by something more specific for those pulled off to the side. He had plenty of suggestions for that second-pass test. As what that first scanner would be 14 years from now, he predicted only that it won't be mammography any more. There probably won't be mammography at all, he added.

Nor will it be the latest current innovation, tomosynthesis. "Five millimeters [the current resolution of tomosynthesis" is about 109 cells," he said. "We should be able to do better than that."
On the other hand, unlike Kuhl, Yaffe could not come up with a suitable alternative. Targeted imaging with nanotech probes is "promising" but much farther down the road than 2025, he said. Other markers, such as diffuse optical tomography of oxygenated and deoxyhemoglobin, may be useful as markers that correlate to treatment results, but probably not for screening. Scanning for hyperpolarized 13C-containing molecules is "probably not" a screening method, either.

"The thing that annoys me," said Kuhl later, "is that we do have [the answer] at our fingertips, which we choose to ignore. If in 2025 we still ignore the huge potential of MRI for screening for cancer, we will have missed the opportunity to save many women's lives."

One session attendee suggested a different possibility: that by 2025 epidemiologists could stratify by low risk those people who don't need screening at all. Nobody accepted the invitation to discuss whether by 2025 breast cancer screening might be not only better, but less prevalent.